Exhaust systems of the type used to direct exhaust from an engine to a location spaced from the engine are well known in the art. Such systems are frequently employed, for example, on stationary devices such as air compressors, electric generator sets and the like and mobile devices such as earthmoving, material handling, and transportation vehicles. These exhaust systems, and particularly those used on vehicles often direct the exhaust to exit at a location elevationally higher than the vehicle operator. In doing so there is usually an exposed length of exhaust pipe in relatively close proximity to the operator. Because the exhaust system passes hot gasses the system itself tends to get hot which requires special treatment of the exposed length of the system.
U.S. Pat. Nos. 4,265,332 dated May 5, 1981 to Lance O. Presnall et al and 3,866,580 dated Feb. 18, 1975 to Gerald E. Whitehurst et al, and British Pat. Nos. 750,170 dated June 13, 1956 and 870,112 dated June 14, 1961 all treat the heat problem by shielding the exposed length of exhaust pipe coaxially with an exhaust stack and pass either induced or forced cooling air therebetween. This solution is effective in reducing the temperature of the exhaust stack but creates several additional problems.
Usually the exhaust pipe is coaxially disposed in an unsupported manner in the exhaust stack. Relative motion between the exhaust stack and the exhaust pipe encountered during normal vehicle operation will cause intermittent contact between the stack and pipe and generate undesirable noise. This noise is particularly annoying to the operator of the vehicle when the exhaust stack is in close proximity to the vehicle operator.
Rigid connection between the exhaust stack and exhaust pipe is not acceptable since engine noise and exhaust heat would be transferred from the pipe to the stack. Also relative movement of the exhaust stack and exhaust pipe due to operation of the vehicle would dynamically load the rigid connection and cause failure thereof.
It is often a common practice in lift trucks to resiliently mount the exhaust stack on an overhead guard by flexible straps and rigidly connect the exhaust stack to the exhaust pipe for support purposes. This arrangement does not permit cooling air flow to be used to reduce exhaust stack heat nor does it permit independent removal of the exhaust stack and exhaust pipe from one another or the overhead guard from the vehicle without disassembling the entire exhaust system.
The present invention is directed to overcoming one or more of the problems set forth above.